Part No. 102916 S-100 • S-105 • S-120 • S-125 4 - 63June 2011 Section 4 • Repair ProceduresREV A LIMIT SWITCHES8-1Limit SwitchesHow to Test the Limit SwitchesThere are 2 types of limit switches: Mechanical(roller arm) and proximity. Mechanical limitswitches are activated by a part of the machinephysically moving the roller arm of the switch.Proximity switches are a magnetic type of switchand are activated by the close presence of aferrous metal.Mechanical Operational Limit Switch:1 Manually activate the limit switch.Result: The limit switch arm should move freelyand spring return to center. A distinct clickshould be felt and heard.2 Connect the leads from an ohmmeter orcontinuity tester to the deutsch connectorterminals in the combination listed below andcheck for continuity.terminal 1 to 2 continuity(zero )terminal 3 to 4 no continuity(infinite )terminal 1 to 3 and 4 no continuity(infinite )terminal 2 to 3 and 4 no continuity(infinite )3 Activate the limit switch. Connect the leads froman ohmmeter or continuity tester to the deutschconnector terminals in the combination listedbelow and check for continuity.terminal 1 to 2 no continuity(infinite )terminal 3 to 4 continuity(zero )terminal 1 to 3 and 4 no continuity(infinite )terminal 2 to 3 and 4 no continuity(infinite )Mechanical Safety Limit Switch:1 Connect the leads from an ohmmeter orcontinuity tester to the deutsch connectorterminals in the combination listed below andcheck for continuity.terminal 1 to 2 continuity(zero )terminal 3 to 4 continuity(zero )terminal 1 to 3 and 4 no continuity(infinite )terminal 2 to 3 and 4 no continuity(infinite )terminal 5 to 6 no continuity(infinite )123456789012123456789012123456789012123456789012123456789012123456789012REV B
